Effects of Turmeric Extract on the Pharmacokinetics of Nifedipine After a Single Oral Administration in Healthy Volunteers

The effects of turmeric extracts on the pharmacokinetics of nifedipine were examined in 10 healthy volunteers. An open-label and randomized crossover study was performed at 2-week intervals. In the control experiment, after a 10 h overnight fast, 10 mg of nifedipine (Adalat® capsule) was administered orally and blood was collected at 0, 0.5, 1, 2, 3, 4, 5, 6, and 8 h. In the combination experiment, the volunteers were orally administered 10 mg of nifedipine together with six tablets containing concentrated turmeric extract (480 mg of curcuminoid per six tablets), which is the general daily dose, and blood was sampled as above. The time profile of the plasma concentration of nifedipine in the control was comparable to that in combination with turmeric extract, as were the pharmacokinetic parameters: that is, the mean ratio of turmeric extract/control group (90% confidence interval: CI); C(max), 0.98 (0.95, 1.01) and AUC(0 - ∞) 1.00 (0.98, 1.02). In addition, the volunteers all completed the study without any serious adverse events. Consumption of the turmeric extract did not affect the pharmacokinetics of nifedipine after a single oral administration.